1. Field of the Invention
The present invention relates to an image signal processing unit which carries out a blurring process for image signals and relates to a camera having an image signal processing unit.
2. Description of the Related Art
Photographing in a shallow depth of field is well known. The photographing in a shallow depth of field is carried out to intentionally blur the foreground and background of a main object being photographed. Such a blurring process is achieved by intentionally placing the background area of the photograph out of the depth of field under the condition that the main object is in focus. The degree of blurring depends on the distance between an imaging surface and a camera lens, and on the size of the imaging surface. The blurring of the background is in proportion to the distance between the imaging surface and the camera lens, and the size of the imaging surface. Consequently, it is necessary for strong blurring, that the distance and the size are maximized as much as practical. Recently, compact type digital cameras, that are smaller than film cameras and single lens reflex digital cameras, have become available. As for the compact type digital cameras, the distance between an imaging surface and a camera lens is narrow, and the size of the imaging surface is small. Accordingly, it is difficult to take a photograph in a shallow depth of field with these compact type digital cameras.